Zinc-smelting furnace.



J. M. HYDE.

ZINC SMELTING FURNACE. APPLICATION FILED MAR.'10| I9I5.

L1%U Patented June 22, 1915.

4 SHEETS-SHEET l.

INVENTOR, WITNLSSES Immas AKLyde, W BY 2 W; #1. M17 I ATTORNEY J. M. HYDE.

ZINC SMELTING FURNACE.

APPLICATION FILED MAR. 10. I915.

Patented June 22, 1915.

4 SHEETS-SHEET 2.

A TTORNE Y WITNESS-ES hmes BY C% m z w; 7% guy: 4% @@ZZ J. M. HYDE.

ZINC SMELTING FURNACE. APPLICATION FILED MARv I0. I9I5. LIM WI Patented June 22, 191.5.

4 SHEETSSHEET 3.

WITNESSES; IN V EN ,1 I .hmes fl ydw, 0 A BY A TTORNE Y J. M. HYDE.

ZINC SMELTING FURNACE.

APPLICATION FILED MAR. 10. 1915.

1 3.4%, Patented June 22, 1915.

4 SHEETS-SHEET 4.

1v T WITNESSES: I V EN ames M. B Y 4? QM ATTORNEY JAMES M; HYDE, OF BERKELEY, CALIFORNIA.

ZltNC-SMELTING l t1 Specification of Letters Patent.

Patented June 22, 1915..

Application filed March 10, M15. Serial N 0. 13,376.

To all whom it may concern:

Be it known that I, JAMEs M. HYDE, a citizen of the United States, residing at Berkeley, in the county of Alameda and State of California, have invented new and useful Improvements in Zinc- Smelting Furnaces, of which the following is a specification.

My invention relates to an apparatus for smelting metal bearing materials containing I zinc or any other volatilizable metal or metallic compound and especially that class of ores containing zinc and other metals such as lead, copper, gold and silver; and has for its object to provide a means for a continuous zinc smelting operation providing means by which the ore and reducing agent may be mechanically fed into the smelting chamber or retdrt and a means by which the material from which the volatilizable metal has been removed may be withdrawn from the smelting chamber during thesmelting operation through a conduit or opening under such conditions that theresidue from which the volatilizable metal has been driven ofi' or a suitable mechanical. means shall act as a seal, so that there shall be no 'efiiux of volatilized metal therewith and noinflux of air or the products of combustion into the smelting chamber or retort. The removal of the volatilized metal from the retort and its condensation shall be provided for by an externally opening aperture from the retort and a condensing device attached thereto.

The present apparatus is suitable for carrying out the process described and claimed in my patent No. 1,118,012, of November 24th, 1914, but is not confined thereto.

This apparatus may be made in a numberof different forms in which its essential features are preserved as shown in the accompanying drawings, in which- Figure 1 is a broken longitudinal section of one form of myimproved furnace; Fig. 2 is a transverse section thereof; Figs. 2 and 2 are broken transverse sectional views of modifications thereof; Fig. 3 is a view similar to Fig. 2 of a further modified form of the invention; Figs. '1, 5 and. 6 are transverse sections of modified forms of smelting vessels; Fig. 7 is a transverse sectional View of a further modification of theinvention;

. Fig. 8 is a partial longitudinal section thereof. v

Referring to the drawing, l'indicates a furnace, having a heating chamber 2, into which fluid or gaseous fuel is supplied by a condult 3, the products of combustion thereof passing by an opening 4 into a flue chamber and downwardly and longitudinally therein to the bottom of a stack 6, by which they are discharged. Extending across said flue chamber in a direction inclined slightly downward are longitudinal series of feed tubes 7, to the upper portion of which are connected tubes 8, which lead obliquely downward from vertical chutes 9 connected at their upper ends to'heating chambers 11, the upper ends of which are connected to hoppers 12. Horizontal gates 13,14 control the respective passages between the hoppers and the heating chambers and between the heating chambers and the chutes. The zinkiferous or other ore, mixed with proper reducing agents (and fluxing agents when desired), is fed into the hoppers and admitted therefrom into the heating chambers. From said chambers the air and moisture contained in the ore are expelled through pipes 10 controlled by valves 15 by means of the heat transmitted through the walls of the heating chambers and derived from hot products of combustion allowed to escape from the flue chamber 6 by pipes 16, into annular chambers 17, from which they escape by pipes 18 into the stack. Said feed tubes communicate at their lower ends with smelting vessels or retorts 19 sloping slightly downward, and extending across the heating chamber. The vapors of the volatilizable metal contained in the ore escape from said smelting vessels by outlets at their lower ends which communicate with condensers 21 in which the zinc or other volatilizable metals are condensed.

In the wall of the furnace are formed oblique conduits 23, which communicate with the lower ends of the smelting vessels 19 and conduct the liquid contents thereof into vertical conduits 24 by which said contents flow into a slag chamber 26, which is here shown as the lower portion of, and continuous with, the chamber 2. The level of the molten material in said slag chamber 26 is determined by the position of an overflow pipe 27, or by other suitable means. Taps 28 are provided for drawing off themolten material of different densities. The conduits 23 and 24 are may be pushed down by suitable implements. They are closed at the upper ends by plugs 29. Instead of these conduits, pipes of the proper material may be used inside the heating chamber.

In Fig. 2 is shown an adaptation of the furnace for discharging the residue from the retorts in an unfused condition into the smelting hearth below the retorts and at the same time adding thereto a suflicient amount of the appropriate flux. 20 indicates a hopper filled with flux and 25 a plunger feeder which may be drawn back far enough to let the proper amount of flux into a chamber 30, from which, at each forward stroke of the plunger, the flux is discharged with a portion of the residue coming down the channel 35. The residue may be discharged above the slag line, permitting the combustion of any unconsumed reducing agent left therein. All channels, including the retorts, through which the charge is passed by pressure or gravity, may be of increasing cross section toward the discharge end and of any appropriat grade.

Fig. 2 is a partial cross section of a furnace of the type shown in Figs. 1 and 2 except that no smelting hearth is provided below the retorts, and means 40 are provided by which the residues, from which the zinc has been driven off, are removed without fusion through the conduits 23 and the conduit 24 and are drawn ofi outside the furnace.

It will be seen that by my improved furnace the operation of recovering zinc and other metals from zinkiferous ore is con tinuous.

In the modification of the invention shown in Fig. 3, which is a transverse section of the furnace close to one end thereof, the

fluid fuel is supplied by burners through a.

conduit 33 to the furnace at one end and the products of combustion escape by a flue 34 at the other end. The zinkiferous or other ore mixed with proper flux and reducing agent is, by means of the hoppers 12 and heating chambers 11, charged into vertical chutes 36, and is then discharged into smelting vessels 37 in a heating chamber 38. The vapor of the zinc or other volatilizable metal escapes by conduits 39 leading to condensers 41. The liquid material fused from the non-volatilizable material contained in the ore collects at the bottom of the smelting vessels and flows by a conduit 42 into a slag chamber 43 communicating with the chamber the level of the molten material in said chamber 43 being determined by the position of an overflow pipe 44.

It will be observed that, in both the forms of the invention shown in Figs. 1 and 3, the lower end of the conduit 24 or 42 is below the level. of the overflow pipe 27 or 44, and therefore below the level of the molten material collected in the slag chamber. The molten material thus acts as a seal to seal the conduit 24 or 42 against the passage of gas through said conduit, either of the vapor of zinc or other volatilizable metal downwardly from the smelting vessel into the slag chamber, or of air, or the products of combustion, upwardly from the heating chamber into the smelting vessel. This is also the case in the modification shown in Fig. 4, which differs only from that shown in Fig. 3 in that the conduit 42 is formed in the brick-work supporting the smelting chamber.

In the modifications of the invention shown in Figs. 5 and 6, the liquid discharge conduit from the smelting vessel does not terminate below the level of the liquid material. However, the same result of sealing the communication between the smelting vessel and the heating chamber is achieved by forming a liquid seal as by a lateral extension 46 of the smelting vessel, either horizontally and then upwardly, as shown in Fig. 5, or downwardly and then upwardly, as shown in Fig. 6.

Any of the forms of outlets shown for the vertical retorts may be used with the horizontal retorts.

In the modification of the invention shown in Figs. 7 and 8, 47 indicates the furnace wall inclosing the heating chamber and the retort structure 48. In its lower portion, the structure 48 is provided with open arches 49, which permit the fused material to pass out into and fill the lower portion of the furnace 47, which is provided with tapholes 50, 51, 52 for slag, matte and base bullion respectively. The level of the matte or slag bath is maintained above the tops of the arches, so that the products of combustion from the gas burners 58, 54 or other heating means have no access to the charge within the retort 48. 56 is a flue leading to a stack for carrying off the waste gases. The retort 48 has an upper portion 57 extending above the furnace and provided with a charging-hopper 58. 59, 59 are pipes leading off the zinc vapors and 61, 61 are condensers therefor. 62 is an internal, longitudinally arranged arch providing a heating chamber beneath the charge and above the slag, and provided with a burner 63 f.- furnishing additional heat to the charge through the arch and directly to the slag. This arch performs the further function of acting as a support for the charge.

The fuel used may be any of the usual forms of solid, liquid or gaseous fuel. When solid fuel is used proper grates will be used for its combustion, or proper means for firing it as coal dust will be provided and proper means provided for varying the heat to the retorts which are to be heated.

1 a rless In the form of furnace shown in Fig. 1, any number of tiers of retorts may be used with any suitable means for continuously or intermittently introducing fresh material to be smelted.

In Figs. 1, 2 and 3, feeding devices are shown by which the charge is mechanically fed to the retorts, is freed from moisture and air before being fed to the retorts, and by which the passage through which the material is fed to the retorts is sealed by mechanical means as well. as by the body of the advancing charge. a The method of using this device is as follows :-While the lower slide 14 is closed, a portion of the mixed charge is discharged from the hopper into the chamber 11 between the two slides. The upper slide is then closed. Heat from the furnace passing around the chamber through the flue l7 heats the charge and generates gas from the reducing agent (a portion of which may consist of soft coal or the like for the purpose) and the generated gas and heat expel all moisture and air which may have been in the interstices of the charge through the pipe 10. When this pipe is giving off strong gas, the valve 15 is closed, the charge is dropped into the feed chute by opening the lower slide 14 which is then closed and the operation is repeated as often as is necessary to supply the charge at the rate at which it is being freed from zinc in the retorts. This type of charging device or its mechanical equivalent may also be used on the type shown in Fig. 7, but the heat and the generation of gas by the heating ing agent in the charge as it approaches the smelting zone will expel the air and moisture from the charge before the volatilization temperature for zinc is reached.

The feed chutes and any portion of the feeding device which it may be well to have inclosed in order to heat the advancing charge, may be inclosed within a chamber which may be heated by waste furnace gases. The screw feeding devices may be of any shape and dimension desirable. They may be made to taper toward the discharge end to increase their propulsive power. Plunger or piston feeders may be substituted for these screw feeders. Likewise arrangements may be made to heat the chamber in which the condensers are located .by direct firing, by waste heat from the furnace or by the heat of the residues when they are discharged outside of the furnace m a solid form. Ventilators may be provided so that the heat of the condensers can be exactly regulated.

In place of the small conventional condensers made of clayware, a large condenser or series of large condensers, may be used to which the volatilized zinc from several retorts may be led for condensation. From of furnace of the reduceach of several condensers, the spelter as condensed may be led by suitable conduits to a single receptacle from which it may be drawn off into molds.

When it is not considered desirable to fuse down the residue with fluxes in the retorts before a part of the zinc has been driven off, charging devices similar to those shown for charging the retorts of the furnace shown in Figs. 1 and 2 may be attached to the front of the furnace to charge the proper flux at the proper rate into the partially distilled charge in the retorts. Where it is not desirable to fuse the charge in the retorts at all, but it is still desirable to recover from it certain metallic values other than zinc, the unfused residue to which no flux has been added previous to the distillation of zinc may be discharged down the conduits into the smelting hearth below the retorts and flux of the proper kind and in the proper quantity may be also charged into the smelting hearth either with or separately from the residue and either above or beneath the fused mass in the smelting hearth from which smelting hearth will be drawn 0d the products of the fusion of the residue and flux as shown in Figs. 1 and 2 and the description thereof. If in discharging the unfused residue through the proper conduit any dust arises which may be car ried out into and pollute the spelter beingcondensed in the condenser, a diaphragm of porous clay ware or carbonaceous material through which the zinc vapor can readily pass, but which will restrain solid matter may be introduced between the retort and the condenser.

Through the apertures at the outer end of the conduits 23 or special openings into such conduits provided for the purpose, samples of the residue may be taken for assay to provide that the zinc distillation is properly performed in the retorts. If there is any further distillation of zinc from the residues in the smelting chamber below the retorts zinc oxid will be present in the gases emerging from the furnace and these may be taken to a bag house or suitable means of collecting zinc oxid.

Where it is not necessary or desirable to recover any metallic values from the residues after the zinc has been removed therefrom, the residues may be drawn off down the conduits to the outside of the furnace and the conduits may have any appropriate type of discharging apparatus which may be so manipulated that a portion of the residue will always remain in the conduit to act as an effectual seal against the gassage of gas out of or into the retort or some mechanical seal such as shown in the charging device shown in Figs. 1 and 2 may be used.

Zincsmelting furnaces are now so constructed that they work onlyintermittently,

- and it is necessary to remove the condensers after each run, so that the residue may be removed and a new charge introduced, after 'which it is necessary to remount the conmolten corrosive material, they may be lined with any refractory material such as chromite, magnesia, car-borundum or the like, or they may be made entirely of such substances mixed with suitable binding material, or fused in an electric furnace.

The various parts of this apparatus may be of any shape or size found convenient and may be combined with any auxiliary apparatus now used in zinc smelting or which it may be found desirable to use in connection with this apparatus without departing from the spirit of this invention.

The charges used in this furnace may be granulated or briqueted. Such fluxes and reducing agents as needed in the smelting operation will be determined for each 'material treated. The proper flux'to use when other metals than zinc are to be recovered will be selected on well known principles by the engineer or metallurgist in charge of the smelting work. Where lime is added in order to get a slag which is fusible at the temperature at which zinc is reduced and volatilized and the fusion of the Whole charge is to take place in the retort, it may be well to have the crude lime-stone first calcined or burned so that it will be free fronr carbondioxid. Wherever possible, charges should be so blended of ores of different constitutents as to require a minimum of barren fluxing material.

I claim 1. A furnace for smelting material containing a volatilizable substance having a heating chamber, a smelting vessel or retort within the heating chamber having an outlet for the removal of volatilizable metal and an outlet for the removal of molten material, a chamber into which said latter outlet discharges, and means whereby said molten material seals against the passage of gas the communication between the latter chamber and the smelting vessel.

2. A furnace for smelting material containing a volatilizable substance having a heating chamber, a smelting vessel or retort within the heating chamber having an outlet for the removal of volatilizable metal and an outlet for the removal of molten material, a chamber into which said latter outlet discharges, a tap for removing the molten material from said latter chamber, and means whereby said molten material seals against the passage of gas the communication between the latter chamber and the smelting vessel.

3. A furnace for smelting material containing a volatilizable substance having a heating chamber, a smelting vessel or retort within the heating chamber having an opening by which material can be charged thereinto having an outlet for the removal of volatilizable metal and an outlet for the removal of molten material, a chamber into which said latter outlet discharges, and means whereby said molten material seals against the passage of gas the communication between the latter chamber and the smelting vessel.

4. A furnace for smelting material containing a volatilizable substance having a heating chamber, a smelting vessel or retort within the heating chamber having an opening by which material can be charged thereinto, having an outlet for the removal of volatilizable metal and an outlet for the removal of molten material, mechanical means for continuously or intermittently feeding the material through said opening, a chamber into which said latter outlet discharges, and means whereby said molten material seals against the passage of gas the communication between the latter chamber and the smelting vessel.

5. A furnace for smelting material containing a volatilizable substance having a heatingchamber, a smelting vessel or retort within'the heating chamber having an outlet for the removal of volatilizable metal, a condenser located to condense the material volatilized in said smelting vessel, an outlet for the removal of molten material, a chamber into which said latter outlet discharges, and means whereby said molten material seals against the passage of gas the communication between the latter chamber and the smelting vessel.

6. A furnace for smelting material containing a volatilizable substance having a heating chamber, a smelting vessel or retort within the heating chamber having an outlet for the removal of volatilizable metal and an outlet for the removal of molten material, a chamber into which said. latter outlet discharges, means for feeding said material into said smelting vessel, means for expelling air from said material during the feeding operation, and means whereby said molten material seals against the passage of gas the communication between the latter chamber and the smelting vessel.

7. A furnace for smelting material containing a volatilizable substance having a heating chamber, a smelting vessel or retort within the heating chamber having an outlet for the removal of ,volatilizable metal and an outlet for the removal of molten material, a chamber into which said latter outlet discharges, means for feeding said material into said smelting vessel, means for expelling air from said material during the feeding operation and for sealing oil the interior of the smelting vessel from receiving air through the charging device, and means whereby said molten material seals against the passage of gas the communication between the latter chamber and the smelting vessel.

8. A furnace for smelting material containing a volatilizable substance having a heating chamber, a smelting vessel or retort within the heating chamber having an outlet for the removal of volatilizable metal and an outlet for the removal of molten material', a chamber into which said latter out: let discharges, said outlet extending to the outside of the furnace to permit the dislodgment of solid material therein, and means whereby said molten material seals against the passage of gas the communica tion between the latter chamber and the smelting vessel.

9. A furnace for smelting material containing a volatilizable substance, having a heating chamber, a smelting vessel or retort within the heating chamber, having an opening through. which material may be charged thereinto, an outlet for the removal of the volatilizable substance and an outlet for the removal of the residue left afterthe volatilizable substance has been driven off, and means whereby said residue .seals against the passage of gas the communication between the smelting vessel or retort and the point at which the residue is discharged.

' 10. A furnace for smelting material containing a volatilizable substance, having'a heating chamber, a smelting vessel or retort Within the heating chamber, having an opening through which material may be charged thereinto, an outlet for the removal of the volatilizable metal and an outlet for the removal of the residue left after the volatilizable substance has been driven off, and means whereby said outlet is sealed against the passage of gas, between the smelting vessel or retort and the point at which the residue is discharged.

11. A furnace for smelting material containing a volatilizable substance, having a heating chamber, a smelting vessel or retort within the heating chamber having an opening through which material may be charged thereinto and an outlet for the removal of the residue left after the volatilizable substance has been driven off, a smelting hearth into which the residues are discharged and in which they may be smelted, and proper means for drawing oif separately from the smelting hearth the various products of the smelting operation.

In testimony whereof I have hereunto set my hand'in the presence of two subscribing witnesses.

JAMES M. HYDE. Witnesses:

FRANCIS M. WRIGHT, D. B. RICHARDS. 

